I discuss the different head designs used on the Predator, the tools I like to use, and what(and why) I am grinding away to improve head flow FOR PURE POWER!!* *Realistically 4-5% gain.
When I only have to remove a small amount as you did I usually just use Tootsie Rolls and that leaves a nice finish also without taking too much off at one time the short side radius is the most important get rid of the sharp edges just like you said but you have to get the shape proper
Great info. I'm about to build two gocarts for my grandsons, and I have 2 non-hemi motors. Once I'm comfortable with their driving skills, I'll be making them faster, and this should come in handy when I do. Thanks for sharing!
If you keep the governor and don't plan on spinning the motor past 3600-4000 rpm, A bigger stock style carb and open pipe will do a lot. They are both really restrictive, especially the exhaust. The exhaust port is a "D" shape 24mm x 30mm. The exhaust pipe is round and 17mm(Yes, 17mm!!) The intake is nearly as bad.
Some times you can get away with a big cam and a governor. When there ready turn the screw a bit. Just food for thought 🤔 billet flywheels should be mandatory with toys
I just ported my 196 head. 18 pound valve springs. I lapped the stock valves a untill i got as much seat as i could. I also polished the dome to a mirror finish to remove any hot spots or stress risers. For my head the area around the valve guide/ valve bowl areas were super rough and gnarly. Stock internals besides valve springs and i smoke my friends stage 2 212
@@WhatIsTheWheel im running a cvt and no govoner on stock internals. 3 years going strong. And i beat the piss out of it on dirt roads and on the trails.
Never watched the video before but I did a little bit of porting on my friends Hemi head. I just matched the intake to the manifold and smoothed out then polished the exhaust. Still hasn't been started yet but can't wait to see how it runs
Unless you plan to go nuts, and weld into the head and plug the oil return , that is the best thing to do. The walls are pretty thin, and they have a decent shape
@@WhatIsTheWheel I didn’t buff the exhaust side. I used scotch brute type pads to smooth it out. The intake was just sanded. It was left rough. I’ll try it again on my other engine build.
It's called a wedge head. The wedge head will have better quench and actually make more HP than the hemi.. But porting them with out a flow bench can ruin the flow pretty badly.. I have had more than a few on my flow bench that customers have ruined,, gotta really know what your doing otherwise leave it stock with just a light blend of the shap edges. valve job and chamber shaping pay the biggest rewards with these.
I would consider the combustion chamber shape a bowl type with the valves perpendicular to the piston face, rather than the wedge which has them both at an angle to the piston and parallel to each other. I would not hog out a port without a flow bench. The changes I made(and what I recommended) were to clean up the sharp edges and polish the exhaust.
@@WhatIsTheWheel right.. it is def more like an open chamber.. I have done some welding in the chamber to give it a more closed chamber design and create a better quench pad, and done some unshrouding around the valve to chamber pinch areas.. raises comp ratio and really produces some punch.. get em around 10.5 to 11.0 and these little engines scream.. Love your vids, I been toying with the idea to start a channel myself.. albeit I do mostly automotive racing heads and induction systems, I think I like the small engine stuff best.. Just more fun really.. Keep up the great work.
@@pablojanski.2559 Pick something you enjoy for a channel, it makes it way easier to create content. I am more of a motorcycle guy but the little kart motors fit my budget much better and I always wanted one. A bonus, at least for shooting headwork, is a stock head is less than $40. Have fun with it, everyone dreams of a channel that generates income but it is better to do what you like and if it makes money all the better. I shoot nearly everything with my phone and edit on the phone with kinemaster(It does a bunch of stuff, way out of my skill level)
After I'm done porting to finish the short turn I use a strip of Emery cloth and feed it through the port out the bowl like floss and use it to round over that sharp edge in the intake and exaust ports and make a nice rounded edge
The diagram of the two heads tells me that the HEMI head utilizes "Impingement Mixing" and the standard utilizes a "Swirl Mixing". I've been recommending "Impingement" for better fuel consumption and better fuel/air mix.
Hopefully mine will hold up. I hogged mine out a lot and put a nice shine on the exhaust port. I didn't put a cam in it but went with the billet rod and flywheel. Had the tools to do it so went for it. It sounded good when It fired up. I put a much bigger carb on it also.
It was tempting to really open them up, but I didn't to create an extra "port". It looks like you can go about 2mm in most spots, but it gets really thin next to the valve guides. Did you do valve springs? The stock ones are really light, and may float even with the stock cam if you spin if you spin it fast enough.
@@WhatIsTheWheel Yes I did change the valve springs. Mind you this was my first time doing port work like this. I have cleaned up a few things in the past. Knowing it only takes a stroke of the burr and like you said you have a extra port, I took my time and did a little at a time. Most of the heavy hogging was from the bowl out being it was just for a yard kart and not having to follow guide lines. I went a thinner head gasket for a little more compression. From the bowl out it has a little more meat to take away.
Good video sir. I’ve been wanting to do some head work but I’m just scared of messing it up. I’m gonna have to just do it, I’ve done everything else(cam,billet flywheel,billet rod,mikuni 24mm flatslide carb, governor delete,header) only thing left is port,polish and shave. Thanks for the info
Thanks, as long as you don't go nuts and hog the ports or accidently grind the seats out you aren't going to screw anything up. It has some pretty sharp edges so cleaning it up should net a little something.
Non hemi you can port it down on the bottom of the intake not on the top look at Paul karts you can get a straight shot and the you fill in the back of the intake
Awesome video the only thing I would suggest because it drives me absolutely crazy as someone who sells air compressors I always hear people rate an air compressor by the capacity of the tank, which is not at all how it should be done it should be by the CFM the pump is capable of producing, the pump and electric motor have no idea the capacity of the system they are pumping into nor does that matter a whole lot. If your pump can produce air sufficiently. A lot of on the road tire trucks only have a 30 gallon tank but have an air compressor that can produce 23 CFM compared to what you were describing was probably a five or six CFM air compressor. 23 CFM on a 30 gallon tank you could open the half-inch ball valve to atmosphere and steel hold probably 60 or 70 psi in the tank constantly. So in short, my constructive criticism is you shouldn’t describe an air compressor capability by the capacity of the tank. You probably don’t care lol. Most people probably don’t care lol but it drives me crazy. 😂😂 happy holidays Homie. Thanks for the video.
I should use cfm. I have a smaller tank compressor now that puts out more cfm so it works better than my big tank compressor did(it is also quieter, and smaller foot print). Still no where as good as the huge twin V twin 500gal setup I had access to when I worked in a truck shop decades ago.
I already did this and install 28mm keihin carburator and change exhaust pipe 24mm to 28mm ...well its outstanding performance for racing longtail shaft outboard hahaha👍👍😁😁😁😁
i took my 196cc clone head apart and noticed there was only 1 valve seal and 1 lash cap. I see your head has only 1 as well. Is that normal? do you know why? thank you, the video was informative.
So what exactly is the reason for only polishing the exhaust port?? Never tried porting but I’m about to give it a shot on my 212 and see what kinda gains we can get so I’m just curious
The main thing is to retain some texture(not polish) on the intake port. If you polish the intake you can get fuel separation and fuel will cling to the port wall(The velocity of the air is lower from drag with a polished port wall and the droplets can "fall" out). With texture you create turbulence at the intake port wall and this keeps the fuel droplets in the air stream. On the exhaust you don't need that turbulence so you get the port as smooth as possible to improve flow. If I had the extra time and money, I would build a dyno so I could see what(if any) gains I was getting. There has to be some gain, even with just smoothing the hard edges, but it is guess work without real data.
Why haven’t the aftermarket people caught on , if it’s so great for flow , then just replace the head with a ported one. This could be done in the casting process so as not to have to machine the material out…
You can get ported heads from several suppliers. Everything from basic stuff to custom castings and heads that have been welded and the ports completely reshaped. Porting has a long hit rod history. Hotrodding a Predator is a lot like hotrodding an old small block Chevy. There are a bunch of mods to get free or cheap power
Will the 212 cc head fit on the 196 cc...I got both and the 212 had no compression may have been cause the intake was missing ..I board the head out...putting it on a 50 cc Honda 4 wheeler..
Good question. You have to watch it with "performance" pistons. I got a flat top recently that is slightly heavier than the stock bathtub piston and it uses thicker rings. More inertia and more drag, not a good combination for high rpm power.
That one spot looked pretty Rough. Looked like U knocked a chunk off ?? Bad for flow. Predator head might be too small to benefit this vs an automotive head. I think the polishing helps & No sharp edges...
U need different rasp bits ,plus udid sorry porting on ports,could port a lot more out 4 flow,,probably 100 ths more 2 be removed out,,open ur eyes u can see it ,,I use 6 in. Shafts on mine
My goal was to smooth them out and clean up the casting. Without going to bigger valves, and a crazy big cam, I don't think I would get that much benefit. Besides that the walls are pretty thin on the top side. You really need to weld in some fill before you go wild enlarging the ports.
You started good ,but ur tooling needs replaced,4 different porting work you left a lot to be taken out 4 flow also,i,I, rate it at a 5 on porting,sorry ,guy!!!!!
Hu. I've been playing with engine's V8s mustangs, vettes, since I was old enough to hold a wrench. I never knew what hemi meant. Hu hemisphere,. Duh. I just figured it had to do with a builders name. Like, rousch or boss or something. Hu. Great info, nicely done.
